Ocular thromboembolic and ischemic disorders collectively constitute the major cause of blindness in middle-aged and older persons, and yet our knowledge of their etiology, pathogenesis and management is far from satisfactory. One of the major factors in this ignorance is the lack of a suitable experimental animal model duplicating the findings in man. Also, there is little doubt that in modern society hypertension and atherosclerosis constitute major public health problems; both disorders individually or by their combined effect not only are the major source of chronic ill health and premature death but also constitute one of the major causes of visual loss due to ocular vascular occlusive disease. The first goal of this study is to produce in rhesus monkeys background ocular vascular and systemic cardiovascular changes, resembling those seen in the vast majority of patients with ocular vascular occlusive disorders, i.e., atherosclerosis, arteriosclerosis, arterial hypertension and high serum lipids with associated hematologic changes. The long-term objective is to study the pathogenesis, management and other aspects of ocular vascular occlusive disorders by experimentally producing various types of ocular vascular occlusive lesions in these animals with atherosclerosis, arteriosclerosis, hypertension and high serum lipids. This is a continuation study where we are producing, in rhesus monkeys, either atherosclerosis by feeding them a special atherogenic diet over a long period of several years, or renovascular arterial hypertension by a Goldblatt procedure or a combination of the two (first feeding them atherogenic diet and then producing renovascular arterial hypertension). We plan to follow these animals for 4-5 years more to get well-developed atherosclerosis, arteriosclerosis and other vascular changes in the eye and elsewhere. After that period, we shall produce experimental retinal vein (central or branch) occlusion, anterior ischemic optic neuropathy, retinal ischemia, or choroidal ischemia; or in some of the animals investigate the response of the optic nerve head to raised intraocular pressure to get a better understanding about the visual loss in chronic open angle glaucoma or low-tension glaucoma. The animals are investigated serially by a detailed ocular examination (including opthalmoscopy, color fundus photography, and fluorescein angiography) as well as systemic evaluation (by recording blood pressure, and by biochemical and hematologic studies). This experimental ocular vascular occlusion in this atherosclerotic, arteriosclerotic and hypertensive monkey model should provide very useful information on the subject.